Normal diesel fuel is unstable. This instability is due to the presence in normal diesel fuel of various olefins, free radicals, sulphur compounds and other reactive materials which can polymerize and react to form materials that impede the engine operation by plugging up fuel lines and filters, as well as fuel injection ports. Gasoline is much worse than diesel fuel in this respect but diesel fuels still can cause problems if stored for period of a year or longer. The diesel fuel of this invention is designed to remedy these problems.
Diesel engines have better gas mileage, lower fuel cost and are more durable than gasoline engines, so they are mounted on trucks, buses, watercraft and the like. The number of diesel engines in use increases each year. Sulfur contained in diesel fuel has presented a problem in pollution control.
Large diesel trucks belch out millions of tons of smog-causing chemicals and microscopic soot, yet face far weaker environmental controls than cars.
While the government pushes for cleaner-running cars and sport utility vehicles, the environmentalists complain that not enough is being done to cut pollution from the more than 5 million tractor-trailer rigs, dump trucks and other heavy vehicles. There is probably no more offensive air pollution than the thick, noxious pollution from big trucks. Environmentalists seek a cleaner burning diesel fuel, along with tougher emission controls on the smoke-belchers.
The Environmental Protection Agency has begun considering a requirement for low-sulfur diesel fuel, although no specific regulations have been issued.
Pollution from large trucks is gaining increased attention as the EPA is proposing dramatically tougher emission controls on cars and popular sport utility vehicles, as well as cutting sulfur content in gasoline by 90 percent.
Trucks, although far smaller in numbers, comprise an equally huge air pollution source as automobiles.
The 5 million large trucks account for 3 million tons of smog-causing nitrogen oxide annually and half of the fine particulates, or soot, that come from mobile sources. Diesel fuel contains almost twice as much sulfur as even today's gasoline. Sulfur inhibits proper performance of pollution control equipment.
Unlike cars, large trucks are not required to have pollution-controlling catalytic converters, nor are they subject to annual emission inspections.
Tailpipe pollution from diesel trucks includes large amounts of soot, which is particularly dangerous because the microscopic particles imbed deeply into the lungs. Furthermore, diesel particles also are toxic and may cause cancer.
Prior Art Patents Murakami et al U.S. Pat. No. 5,730,762 teach a diesel fuel of reduced sulfur content which contains an alkyl side chain on the aromatic ring and also contains hetero nitrogen compounds with an alkyl side chain. The composition also includes carbazole and indole compounds as components of the fuel composition.
Nikanjam et al U.S. Pat. No. 5,389,112 disclose a diesel fuel with low aromatic content and high cetane number. There are controlled amounts of aromatics in the fuel to produce an optimum cetane number as defined by a graph set forth in the patent. The fuel can also have added thereto a cetane improver. The composition also includes 2-ethyl-hexylnitrate as the cetane improver.
Cook et al U.S. Pat. No. 5,814,109 teach an additive for improving cetane number and/or lubricity of diesel fuel. The additive is prepared by the Fischer-Tropsch hydrocarbon synthesis. The composition also includes C.sub.14 -C.sub.16 linear primary alcohols.
Russell in U.S. Pat. No. 5,792,339 discloses a diesel fuel which minimizes the production of pollutants from vehicles by adjusting the amounts of aromatic compounds in the fuel. The composition also includes polycyclic aromatics of between 5.0 to 8.6 weight %.
None of the prior art references discloses diesel fuels for diesel engines used to power vehicles such as trucks, buses and boats which is formulated to produce less pollution and run the engine efficiently.